Hi i aint got the biggest arms im a small chap just enjoy working out but im right handed and my left bicep and left forearm are about a half an inch smaller than the right its not that bad if you glimpse but when i tense my forearm and bicep up you can tell the difference how do i bring my left upto scratch qucik ive been lifting my dumbell's just on my left and isolated my right for a while but not showin any improvement any help thank's.